SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a659922c1f6018522c344008bf1ce278ffbb1045f5f095e917b0088f3bc0a14f' 
  AND token = 'gOJ992Cs5xTAQy+WqXjHd+Y1pOOaPnFC9d6KKM337xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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