SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ef6cb242f2fc1718e9ffa7e96d4ec75468c853a445f19ca79c7ae6d91c26875' 
  AND token = 'BzyY/wVPPgJQcFpMlYf1AZJjVbAYTFK9wJ73uIVSo1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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