SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '779cbcf1d9651a808e60c642f26a5732b3ce0a0d55144305034937afb0b1f3ab' 
  AND token = '9YAevI6W4OkhLfLdeq+WGlVIYxUeFCd5XIBqqaZD/S4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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