SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5be88d092601bf3668127bf4ff4b7a0ec0e414496de2068fc3cdbdba63a5993' 
  AND token = 'LtIfjmt+drJ/wy0Lq5Clirghu6ZWm+qVcwO6OuZ2ZFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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