SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793375fec6ec222aac5b71909206a6c5d6cd05b498487218cf199c8bd3deda23' 
  AND token = 'GV55I9NQ0OgGCLlMzJ1M+Dq+gk4q8NB01H134EmzsQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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