SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea7431c641c284374363b5654fbcdac8dfc9479fa287f8f36ba97009c9220d4d' 
  AND token = 'nhO5b/0Nu3j9P1jZxIb2bgb6N+Q7fE/+nqtj4zBhKxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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