SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a38774cd1a8ae86f7195b145400c8f14f42871318a1b26d5b77a1108881497c3' 
  AND token = 'LJiHHvdMXCgmjbsVxRGlbib/KQ4oiv+5s/XbVHmyvbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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