SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a781a4ce64d81d7873969925bf1f58e5ee116206708e0e5b26e0094b2c68c3a9' 
  AND token = '5mtnbpb3j7U5Qj0mM86rOwcF2k/tanQfn7pviwjIZ7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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