SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01f6457e17bda2c1376ce95880ee1abc70ef166271490de8fe878d447b7a59c2' 
  AND token = 'U8sdyz+vTbZMDwimGgxziVriBjwC+u/rlZReUtDGSbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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