SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e3ac4d73d558871a1f8250aae81e692aeac099851a0a19bffc069ac59b1462' 
  AND token = 'RBccjYfhqufySHPI1r55d7+OxSnB6tpnYLjDDi36R1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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