SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9857cca94236c56d917f6fa6e883a93f2dc266f992a219629dfd47236c9a411' 
  AND token = 'GJnHd7BMqGBHCXgssNZZgcvZK5IIBoeGvKhO+WVCHXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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