SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc46d544e74219f1d0175624bf1e962320a22b6953103a862b135caf45dac4d' 
  AND token = 'agqpwWTjZixW+3c0gN04siBy07IzBV3Anhr0f4UejPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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