SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ffc18ac6cc614cd0e7c5adaca58cb839f4b80e342df6588d169a16cc3a39b620' 
  AND token = 'gzk+mouUCRKUgcQ6IuZUsnsshGW4cxhfRK4OExTtVHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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