SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26aaa861d667a4402d2ba3a52a0267c79f432a3846fa9e9863e582fab15975a8' 
  AND token = 'm/89qJFtDxE6K1nlzwcO+S0TTolHkJ+WIqvgmp7rz4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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