SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5365e5aede64b2ae9345263a8a1e64e37a1624ac4b10a9427109d9264655bb65' 
  AND token = 'gynZ0Tj7f+KlgxleDnMQLKUAE5+CQLLtcxn2WcwWGsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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