SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c366db21f168a40aed2d7aed89501a53bdb0f1c30bcba188a13f617084b9cfb6' 
  AND token = 'Y4WuVlDZ9IAsJc8hjguzBdrtcjj09iuHPCGEyzIsYlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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