SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc115cb76b1d690f848a5cf137d301b8d57ff191015091a276f1be14a487881' 
  AND token = 'H3Fz+NmshQ/pDGTPvIxPPL793HotedYmHS9IwbtgDeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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