SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f740fccfae0adaa2d39e23c8a1b8efd35fa056f01f7facb8b7a8e891b945b6fe' 
  AND token = '0z2+CJVK2y4qFJoLxgLVv6fKePJhuLPY5nLzZl3VPLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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