SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ad405021170552507bc382d04aeac54bf9bc0f978c0cd4a5718fbb32dbe6328' 
  AND token = '43VGnp2cj8tSLKjLe2z/za9MbK8ZI5HfAHa7bvyEdfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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