SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc5a291694f3fcc432a9d4b2b0313b703b3d7d174953f0df010da1548b57ea26' 
  AND token = '5R9P1qH7YFu7ZCJw3id+u4jzFEkIntOP8cmAJ5pBNAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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