SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '068c46ba7d6fff0cf633a5fed22592cc0fcda2b0a3814cc1e94547f549f65968' 
  AND token = 'NxKgsEJ8Za29khl7/tPYoxSNd1GLdh6fVe49twdKpyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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