SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b519ce004e1e98e5ea6aadabc77921c6d0854790fcf505378d496849e11f7ea' 
  AND token = 'QAEfhul9CPDvX5GYpH/CecVywcM1clz2G3T/uDLv/ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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