SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81978e509ee01beff9b8aaaa4ef0142f5c261643010c7f5d4d723b14b3aa404b' 
  AND token = 'tVYi8zHUteTrJv6w+1PA1kGohxw6cXqzfbTUfJKMFNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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