SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3ba094c9f60c1f0d5517e1598c83644de93ec9abe8cfc313b623bbbd7961f0' 
  AND token = '+ljh0rU7GnqFvGzOzPj3Cs3UvvvIZFpyV2dVfRpgnlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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