SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e266e33b08f8e3cfb899b00e9b3465705780488b86d6412c0a32b7dd758e47' 
  AND token = 'j36erwpVVh+t3Nd1d0PtBY6HZZ9uCe3lHJTNKTMDoFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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