SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd5b0486d0fb995c5785fc7fcfa08b21c84108d03e24d321100d2457a7e3e0321' 
  AND token = 'NOtbkzoezXO8z0ENbI1HuG69clr8qcNpCCWecLDqK7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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