SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd29ddf204736a80276f293f6190bd8d1da45597bc055d3448c7e96fc3bd4264a' 
  AND token = 'u9SBqeluuO1Dv5LbjFjZZDtmORujOHDvFzsOdkU221k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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