SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '715d1313c9dc888882b96542a77fa29a03e380ab7ebe755e377513b0ca57354c' 
  AND token = 'WxVqr4mxvkPzYuDNAum2v4AdXL8lCTvI4kWN5ws4o08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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