SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd6c7846287e199efdd63ad9b807a02a598f7711be98f1829b928b164d1388294' 
  AND token = 'hgcqnGFRi5bbecCpC+Mg338bQ38u+ja+dAY0CYo4uYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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