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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfdf3b204ab2ffd5e3be45b49ca2af84d14a694e1b5ca8d6fc93f2d2ff03386f' 
  AND token = 'mk4jNDU0wsgCBduYUyp5DSBpINlMZHUncyMoDtCyWl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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