SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c465cf35a9dfea73b03c70e51d691f8390bde6517c85f754102ec0ba57a9444' 
  AND token = '9bVkpeJVZwz22fFsV/vgXlCX5Vm1xAkpDD9AqwNbkMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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