SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7dabd20263f1f6e74b763d5bb63e6089e2f226975d15556be6cf4f7c972d2586' 
  AND token = '4raeJmtcUF0m4qbvqgrv4sd25F2I1PUkRBq0rqv05PA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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