SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0a8c7846ac55a4bd3f76395c878b8cd627f713ad390a1fb3d9866607c99f024' 
  AND token = 'SL881DzStIBjNvi3GrrqKorH4Je7Yr+q2o4fC9KopGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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