SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eefcf36b8e33a431523f5b091fd35e2528f0862e69a079f71184a7757f289007' 
  AND token = 'E0lWeW8m897ZP9DackcfNjeQat5tDvyEsEjSCik+/Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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