SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a61e34c20489df603b58ee6f1ae6237b6fd6602070117cc0dbf019967df1e450' 
  AND token = 'XbXLaiUhlPWLH3Bje40BMq6V0ejqfqzrLPJvH9cz9uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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