SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f0b0c752f42d516944a98c68603f76312af939c5f4a5d13af39cb04ce2a07da' 
  AND token = 'G10dvuVYgMW8HUMybBVLZIwhCOJd9T60h2CrY7mxk1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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