SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cd4d4e83387a0cde0248d174ae4eefe87e36c76f17541395bb6dccf1ba8bc6f' 
  AND token = 'W5dwlnsdMD5pRKZkAl3TexH1PdTZ/iZPsv+y0EiXPNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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