SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc9fda5059d7f42c97730db47a0ab994f7bb77dc75bf644c9007230a252618c6' 
  AND token = 'BNTzubH9Lc2lpLXJPWiW+vYoeTAwiTUB+22GEYCMTa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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