SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4815ec2b639aa1e85c701805849d271af3b97f2838120a73222e8da9669466b2' 
  AND token = 'iKDnUqfNbdids6ZHkCfI5z7u+a4PdwT54wloElMRGu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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