SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb4baf014d51fe2d8a52f060ea338aa1ad679f1b6c792d2f6b0e4d1f0a4f7b8' 
  AND token = 'Dzd6JXvvw9/YW1Vh8MTNmjUp50iZJg7visiczxkIhHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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