SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f57e962b90d873dd99bcc7897c0603011ab46a7afea8b12ac470cbd00a878fe4' 
  AND token = 'Dkf2hLFrnP05g/CDgTDreobQr0EcISFYOpCKiGch4YE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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