SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8c1ccb40ebd6f30d05236ce0d591377284279c95026321cacf7307827abee5' 
  AND token = '234sk5YSP/2Weyan5XnfjcgmSDLHHtAPvnlpnHG+xhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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