SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '301538e1b0ae7db88c863b1089de5472d43e436a04e994872e2dcd758492eacb' 
  AND token = 'fMVW9SGNj8SMMSdrGEGfqJi9MfrDqYgOaXrSH3JgjN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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