SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd556d9d35d912781c3b906ec0167c8e4e4e3b1d2e47924756ff38daba88db035' 
  AND token = 'ujpZ8fLBqVFYhyzJssX1YZUF9RZ7dujyoqqf/kEgpEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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