SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '283ebd05a2bff4ae0351048d1eac97c3dde826c4cd1d224085c673d035f32dab' 
  AND token = '40ddkeU2gM7hNRTRAxF3sDs2hji242pKJN0htIUuorc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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