SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f59cc3da5c394aa2fae1d87c7f97611581461caabaf27b149decdd7d878a76ac' 
  AND token = 'Y35LG0QvoC3xCZQYOkdrA0DLujUbV4ctlesuL6oxXnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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