SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8faee949f350d3e1e171fa824cb89d636968372075d4dc8df8ae8a9f2cfdabb6' 
  AND token = 'haXgWIPUrkyoqd5oGrBHT4tnGy6F1LwiV6pxjcAT/H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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