SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '654bef85e8289e0603d9ca984ccd4bf0377084943fd5012d960f7268fd790272' 
  AND token = 'B5gUmn5XeI8rpuwSOWK+5/TqM1rGgRYr8EL96j6moFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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