SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd930667c1db35b522f1321ab77498248127231323c2febccc9c8f5487cd15a3a' 
  AND token = 'BRksVwRtWDK4BUn7BX5FZtuvYg2MrtZCILVpZymYeCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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