SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af98cbb8ffce301d4c8e44d1c8ff17b7ded801fcaacce873e36c1b9624af269' 
  AND token = 'vPzfoQxybzqlxZdwTzKHOL9cR/f/QbUbT5JTKEG1/7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}