SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '431f5dd6b74b6c91242d24888dc4e373944a445cf50114517983130be61e680c' 
  AND token = 'LHVedoO8ay0JeKhlcWhldzyEDuXH4UdrfxKkNfz6sEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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