SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '997430273a4494775c493a2f94630452da16a42167562a70f67dda06cb2e4bd3' 
  AND token = '3MTQXp/49EZZsP7pUil88SLETc+h3ePAPjipAoI2U1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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