SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a209aa70d68145d407677cf4447b7f4f1cd37452da689fefe02477c0e54efa71' 
  AND token = 'ckT9cWtLIg08VLmpYYp2aWuSTYrz3Ab3qelQe4GfbsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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