SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4210418b97c8c178299cd04d7a39c1277b60a11feb21825d1ae47b40b3d522' 
  AND token = 'f9nw4dzU3rpNWdw7LpwgYvP4FQgCuPxvxymIjk1Et6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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