SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e87acd8dd39418028f037ce2367770b30c5723f0c771da1e7f918285e4fe39f' 
  AND token = 'ZVSKCd+hdl1AXvGXrQB1NVCJKbsWzuHtYYHPkFv4M2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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