SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f49b04691b7fb97e1873fb2d825d43859043c0816a6c5a76733b1140c3b283e' 
  AND token = 'd6w39BB++lE6FsKLpHpyIKXZi9ZF7voYQ5A2L2fhWJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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