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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3c33a824a2ef0fab55fbbf69e81f40f739557006b9a2800a1eb6f2670d00537' 
  AND token = 'Xl0oWhPZ2vuJaOY0vP+OhO+JdleYo27UlkUIDd/7G7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}