SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12091347628cf75a37342febfe32f1049daf9e2af63d95c31b8f79ed4984a264' 
  AND token = 'ETtzRcNIKyDKryDS0aLX9P3aFngCKwiEcc/bn5I2fCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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