SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c5b316faf1110637409161bfd13d2142fdbb4482a068a2de9cbfec89f3ea9e' 
  AND token = 'CGJl4S5tFwugkoMt49qeTIOcuWu7+cavG8sKT9TBoAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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